# Technical papers or monographs without a single mathematical equation

Recently, I stumbled upon a historically important monograph on a technical subject, which explained complex physical phenomena without a single mathematical equation. I forgot the name of the author, the work, or any other identifying information. Therefore, I ask this question with two goals in mind: first, rediscover the work (some details below); second, find out if there are other similar examples, especially written by people who otherwise have unquestionable mathematical proficiency.

The monograph I read was written between 16th and 19th century, it may have been on a topic related to light (electromagnetic radiation) or optics, and it was quite a voluminous work with maybe 100 pages. For some reason I think the author was someone of the likes of Christiaan Huygens, Thomas Young, or Augustin-Jean Fresnel, but I am not sure if it is any of these three. I also believe he was English, or the work was written in English, but I am not sure about this either.

• I do not know how to answer this question, we propose titles and you check? Could it be Micrographia? Sep 20, 2023 at 16:11
• Micrographia is not the text I had in mind, but I think it fits the criteria outlined in the question. However, I think works that pertain to physics or engineering, where you would expect to see maths, would be more suitable examples. Regarding judgement criteria, it should be possible to read the work, which narrows down the search. Alternatively, the work may be known for this peculiarity (lack of equations), which was certainly the case for the one I am looking for.
– Klig
Sep 20, 2023 at 17:21
• Newton's Philosophiæ Naturalis Principia Mathematica (1687) have no equations, despite the title! There are only geometric proofs with pictures. It is about 100 pages. And he had mathematical proficiency, especially in calculus, I suppose! Sep 20, 2023 at 18:58
• It could also be Newton's Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light (1704) which relegates the mathematical formulas to book III. Sep 20, 2023 at 21:15
• Notation for equations was not developed until 16th century, so earlier authors, who wrote on geometry, algebra, mechanics, optics, astronomy, etc., expressed themselves verbally with occasional diagrams. From Euclid's Elements and Ptolemy's Almagest to Islamic authors like Omar Khayyam and Ibn al-Haytham. It was still common in 17-18th centuries, so it is not exactly a distinguishing "peculiarity". Of recent books, Mandelbrot's Fractal Geometry of Nature has surprisingly few equations, although it is not "without a single one". Sep 20, 2023 at 23:54